Method and apparatus for controlling yarn coatings

Abstract

An apparatus and method for controlling yarn coatings such as sizing are provided which includes nuclear radiation detectors which measure the attenuated radiation through processed yarn. Before and after radiation measurements are signaled to a computer which is programmed to generate a signal which controls squeeze rollers that adjust, according to specific size requirements. A second embodiment of the invention is provided for processing tire cord webs and utilizes digital line scan cameras in conjunction with the radiation detector sensors. Line scan cameras provide an opacity measure to determine yarn count and maintain an accurate density measurement even as lateral shifts in the web during processing occur.

I claim: 
     
       1. A yarn sensor comprising: a yarn guide, means for generating radioactive emissions, said emissions generating means positioned proximate said yarn guide to radiate yarn passing along said yarn guide, means to detect radiation from said emissions generating means, said radiation detection means opposingly positioned from said emissions generating means relative to said passing yarn, a means to measure yarn opacity, said opacity measuring means positioned proximate said radiation detection means, a microprocessor, a yarn evenness sensor, said evenness sensor joined to said microprocessor and said microprocessor connected to said radiation detection means. 
     
     
       2. A yarn sensor as claimed in claim 1 wherein said yarn guide comprises a rotatable wheel. 
     
     
       3. A yarn sensor as claimed in claim 2 wherein said wheel comprises a pulley. 
     
     
       4. A yarn sensor as claimed in claim 3 wherein said pulley comprises a v-shaped groove. 
     
     
       5. A yarn sensor as claimed in claim 1 wherein said yarn guide comprises a pair of rotatable wheels, each of said wheels positioned on opposite sides of said generating means. 
     
     
       6. A yarn sensor as claimed in claim 1 wherein said radioactive generating means comprises a radioactive isotope. 
     
     
       7. A yarn sensor as claimed in claim 6 wherein said isotope comprises Technetium 99. 
     
     
       8. A yarn sensor as claimed in claim 6 wherein said isotope comprises Promethium 147. 
     
     
       9. A yarn sensor as claimed in claim 6 wherein said isotope comprises Krypton 85. 
     
     
       10. A yarn sensor as claimed in claim 6 wherein said isotope has an energy distribution of not greater than 0.3 MeV. 
     
     
       11. A yarn sensor as claimed in claim 1 wherein said detection means comprises an ion chamber. 
     
     
       12. A yarn sensor as claimed in claim 1 wherein said detection means comprises a solid state scintillation detector. 
     
     
       13. A yarn sensor as claimed in claim 1 and including a moisture sensor, said sensor joined to said yarn guide. 
     
     
       14. A yarn sensor as claimed in claim 1 and including a shutter, said shutter attached to said radioactive generating means to terminate radiation therefrom. 
     
     
       15. A yarn sensor apparatus for measuring the change in the density of processed yarn after sizing to control the sizing application comprising: a first nuclear emission sensor, a means to process electronic data, said first nuclear sensor in communication with said electronic data processing means, a second nuclear emission sensor, said second nuclear emission sensor in communication with said electronic data processing means, a sizing applicator, said sizing applicator positioned between said first emission sensor and said second emission sensor, said electronic data processing means communicating with said applicator, means to measure opacity, said opacity measuring means positioned proximate said first emission sensor, whereby said electronic data processing means controls the size applicator to regulate the amount of size applied to the yarn. 
     
     
       16. A yarn sensor apparatus as claimed in claim 15 wherein said nuclear emission sensor comprises: a yarn guide, means for generating radioactive emissions, said generating means positioned proximate said yarn guide to radiate yarn passing therethrough, means to detect radiation from said generating means, said detection means opposingly positioned from said generating means relative to said yarn. 
     
     
       17. A yarn sensor apparatus as claimed in claim 16 wherein said yarn guide comprises a rotatable wheel. 
     
     
       18. A yarn sensor apparatus as claimed in claim 15 wherein said radioactive generating means comprises a radioactive isotope. 
     
     
       19. A yarn sensor apparatus as claimed in claim 18 wherein said isotope has an energy distribution of not greater than 0.3 MeV. 
     
     
       20. A yarn sensor apparatus as claimed in claim 15 and including an encoder, said encoder positioned in contact with said yarn to measure the stretch thereof, said encoder in communication with said data processing means. 
     
     
       21. A yarn sensor apparatus as claimed in claim 15 wherein said opacity measuring means comprises a digital line scan camera, said camera positioned behind said first nuclear density sensor, said camera communicating with said data processing means for determining the opacity of said processed yarn. 
     
     
       22. A yarn sensor apparatus as claimed in claim 21 including a second digital line scan camera, said second digital camera positioned behind said second nuclear density sensor, said second digital camera communicating with said data processing. 
     
     
       23. A method for controlling the coating of yarn during processing by comparison to a known yarn density comprising the steps of: (a) determining the density of the yarn before coating;   (b) sensing the evenness of the yarn;   (c) measuring the opacity of said yarn for use in density determination of the yarn;   (d) applying a coating to the yarn in a continuous process;   (e) determining the density of the yarn after coating;   (f) computing the differences between the determined densities;   (g) comparing the difference in density to a known density; and   (h) adjusting the coating application accordingly.   
     
     
       24. The method of claim 23 wherein the step of determining the density of the yarn before coating comprises: sensing a yarn increment with a nuclear density sensor, and transmitting data from the nuclear sensor to a means to process data. 
     
     
       25. The method of claim 23 wherein the step of applying coating to the yarn comprises: applying a sizing solution to a web of yarn and thereafter drying the web. 
     
     
       26. The method of claim 23 wherein the step of determining the density of the yarn after coating comprises: sensing the same increment of coated yarn as sensed before coating with a nuclear density sensor, and transmitting data from the nuclear density sensor to a means to process data. 
     
     
       27. The method of claim 23 wherein the step of computing the differences between the determined densities comprises: subtracting the density obtained before coating from the density obtained after coating. 
     
     
       28. The method of claim 23 wherein the step of comparing the differences in density to a known yarn density comprises: comparing the density difference to a theoretical yarn density. 
     
     
       29. The method of claim 23 wherein the step of adjusting the coating application comprises: decreasing the amount of coating applied to the yarn.